Momentum and energy distributions of nucleons in finite nuclei due to short-range correlations

Abstract

The influence of short-range correlations on the momentum and energy distribution of nucleons in nuclei is evaluated assuming a realistic meson-exchange potential for the nucleon-nucleon interaction. Using the Green-function approach the calculations are performed directly for the finite nucleus 16 O avoiding the local density approximation and its reference to studies of infinite nuclear matter. The nucleon-nucleon correlations induced by the short-range and tensor components of the interaction yield an enhancement of the momentum distribution at high momenta as compared to the Hartree-Fock description. These high-momentum components should be observed mainly in nucleon knockout reactions like (e, e ′ p) leaving the final nucleus in a state of high excitation energy. Our analysis also demonstrates that non-negligible contributions to the momentum distribution should be found in partial waves which are unoccupied in the simple shell-model. The treatment of correlations beyond the Brueckner-Hartree-Fock approximation also yields an improvement for the calculated ground-state properties.

Self-consistent Green's function method for nuclei and nuclear matter

“…These calculations suggest that most of this strength is found along a ridge in the momentum-energy plane (k-E) which spans several hundreds of MeV/c (and MeV). Moreover, although the distribution of this strength accounts only for a small fraction of the total number of nucleons, it is responsible for as much as 60% of the total binding energy of the system [150]. As a consequence, the present understanding of nuclear correlations would gain important information from the experimental knowledge of this distribution.…”

“…33. Results for the momentum distribution and true potential energy based on the spectral function show that enhancements as large as 200% for the kinetic and potential energy over the mean-field values can be obtained for both nuclear matter [61] and finite nuclei [150] (see Sec. 5.3).…”

“…5.9. Solid theoretical arguments [149] and calculations clearly pinpoint this strength at high excitation energy in the hole spectrum both for nuclear matter [60] and finite nuclei [150] (see Sec. 5.3).…”

“…The approach introduced in Refs. [202,183,150] computes the self-energy for finite nuclei in terms of a G-matrix which is obtained as a solution of the Bethe-Goldstone equation for nuclear matter…”

“…The latter was studied by Benhar et al [179], for different nuclei using nuclear matter results and LDA, and in Refs. [183,150,184] for 16 O using the Green's function formalism. These calculations suggest that most of this strength is found along a ridge in the momentum-energy plane (k-E) which spans several hundreds of MeV/c (and MeV).…”